April 20, 2013 Earthquake: Longmen, Sichuan Province, China

Felt Report

At least 196 people killed, 11,470 injured, 21 missing and 237,655 displaced in Sichuan. Many houses collapsed or damaged, roads damaged, communication interrupted and power outages occurred in the area. Felt (V) at Chengdu, (IV) at Chongqing and (II) at Xi'an. Felt in much of Sichuan and in parts of Guizhou, Hubei and Yunnan. Also felt at Khonsa, India and at San Sai, Thailand.

Tectonic Summary

The April 20, 2013 UTC Mw6.6 earthquake in the Sichuan province of China occurred as the result of east-west oriented reverse-type motion on a north-south striking fault. A preliminary source location suggest the event likely occurred on the Longmenshan fault or a tectonically related fault at a depth of 12km. The Longmenshan fault was the source fault of the May 12, 2008 Mw7.9 Sichuan earthquake. The preliminary April 20 event location is approximately 85km from the hypocentral location of the 2008 Sichuan earthquake. The April 20 earthquake reflects tectonic stresses resulting from the convergence of crustal material slowly moving from the high Tibetan Plateau, to the west, against strong crust underlying the Sichuan Basin and southeastern China.

On a continental scale, the seismicity of central and eastern Asia is a result of northward convergence of the India plate against the Eurasia plate with a velocity of about 50 mm/y. The convergence of the two plates is broadly accommodated by the uplift of the Asian highlands and by the motion of crustal material to the east away from the uplifted Tibetan Plateau.

Four events of Mw6.0 or greater have occurred within 200km of the April 19 event in the past 40 years, including the May 2008 Sichuan earthquake and a subsequent aftershock. The northwestern margin of the Sichuan Basin has previously experienced destructive earthquakes. The magnitude 7.5 earthquake of August 25, 1933, killed more than 9,300 people, while the May 12, 2008 killed 69,197.

(above from reference #1053)

A powerful earthquake struck the steep hills of China's southwestern Sichuan province on Saturday, leaving at least 156 people dead and more than 5,500 injured, nearly five years after a devastating quake wreaked widespread damage across the region. Saturday's quake, while not as destructive as the one in 2008, toppled buildings, triggered landslides and disrupted phone and power connections in mountainous Lushan county. The village of Longmen was hit particularly hard, with authorities saying nearly all the buildings there had been destroyed in a frightening minute-long shaking by the quake. (reference #10505)

A strong earthquake that struck the southwestern Chinese province of Sichuan this weekend has killed 186 people, sent nearly 8,200 to hospitals and created a dire dearth of drinking water, Chinese state-run Xinhua reported Sunday. (reference #10507)

196 dead, 21 missing, 13484 injured, 6.8bn USD total damages (reference #13045)

198 deaths, 14785 injured, 6.8bn USD total damages (reference #1250)

217 deaths, 15554 injured, 10.819bn USD economic loss (reference #13727)